Nearly 4,000 students who formerly attended public schools are receiving tax money to help pay the cost of private school under Indiana's school voucher program, which is believed to be the nation's largest, officials say.

Advocates say the voucher program is meeting expectations in its first year, despite a late start due in part to a legal challenge. Although the program's first-year cap of 7,500 was not reached, its proponents say that they're pleased with the level of participation.

"We had only a short window to implement the program," School Choice Indiana Executive Director Lindsey Brown told the Evansville Courier & Press. "We were never concerned we were going to hit the cap."

Gov. Mitch Daniels and the GOP-led General Assembly this year gave Indiana the nation's broadest private-school voucher program in the country. Supporters say voucher programs give parents more choices about where to send their children and force public schools to be more competitive, but opponents say they drain funding from the public school system and wrongly divert public money to private religious institutions. A group of teachers and religious leaders is suing to overturn the law.

Under the new program, vouchers can cover up to 90 percent of the cost of tuition, depending on a family's income. The actual value of the vouchers is less than the amount of tax money a public school would have received for that student. The maximum value for students in first through eighth grade is $4,500.

School Choice Indiana says 85 percent of the students who have received vouchers qualify for free- or reduced-price lunch and 53 percent are minorities.

Sixty-nine percent of voucher recipients are from metropolitan areas, while 16 percent are from suburbs and 15 percent are from rural areas.

Indiana's program will be limited to 7,500 students this coming school year and 15,000 next year, but then there will be no limit on the number of children who could enroll as long as their parents fall within income limits. Families of four currently earning up to about $60,000 a year could receive them.

"We're not super-concerned about hitting the cap, but the longer the program is in place, the easier it will be to spread the word," Brown said. "I think you'll see it grow quite expansively."